As far as I have experienced here are a few don'ts for eels that will kill them.
* Don't leave them in sun or warm area's. Cool is good. Drak is good. Damp is
good.
* Don't leave them in water for more than a few hours without changing
the water to reoxygenate it.
* don't ever, ever use chemicals, soup or other cleasners or chemicals in
a bucket you are going to put eels into.
* Don't let their skins dry out.
* don';t put ice cubes directly next to them. They will freeze to the cube.
* don't leave them outside overnight w/out racoon protection on top of their
container. They make tasty coon treats...
* Don't troll them at speed as your zipping from spot to spot; bring them out of
the water, and let them dangle or rest on your boat deck. Eel's are tough,
but high speed trolling kills them.
* Oh yeah - don't leave an uncovered bucket on your boat w. eels in it
overnight. Gull's love em also.